wiring outdoor hot tub


Old 09-29-01, 10:00 PM
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I am in the process of installing a hot tub outdoors.
I plan to get the permit, have the electrical inspection done, but I enjoy learning new things(without them doing me/family in).
My plan is to come off the main box with a double pole 50 amp breaker,come accross(perpendicular to their[the joists} run) the floor joists in the basement storage area where the main box is.The run continues into a crawl space, which allows/gains access to my attached garage area. In the garage, the run will go through a set of base cabinets, and end at the outside wall.Run at this point measures 60-70ft. Once through the outside wall the run enters a sub panel(?)50 amp GFIC/Quick disconnect box. From here it wiil do a 3-4 foot drop down to grade,and travel below grade 20ft where it will surface, about 2 ft. from the tub's external skirt(access hole), which sits on a 4 inch thick patio slab.
That describes the total run, more specifically, I plan to use sched #40 pvc with (3), #6 gauge(hot-red/hot-black/white-neutral) & (1), #10 green insulated ground (all THWN wire)from the main 50 amp breaker to the 50 amp gfic/quick disconnect box.Coming off the gfic/quick disconnect box, I plan to switch to Sched 80 pvc, and continue with the (3) #6/ & (1) #10 grn/(unspliced at this point). This will travel 18 inches below grade, and terminate at the tub's access hole in the skirt.
The siding on the house(which will be within 5 ft of the tub) will be bonded to grn ground bar at the gfic/QD box with #8 bar copper wire, and a star washer to house's siding. The gfic/QD box is in sight of the tub, and as I mentioned about 20 ft away(farther than 5 ft but less than 50ft).
There is an outside flood light about 5 ft away and 5 ft higher than tub surface. This I plan to put on a separate GFIC circut. I have an external outlet about 18-20 ft away from the tub, which also will be GFIC. My understanding is that I need one outlet at least 5ft< <10Ft from tub on GFIC, which I plan on installing.
As for the system's GES, what I have in place is from the house when it was constructed back in 1989, by the contracter. I am the house's original owner, and have not modified this at all. There is a #4 or heavier black(cable like) wire that runs accross the basement storage area floor joists, and attachs to the water pipe at about 18 inches from where the water pipe emerges from the concrete floor slab,from it's underground access. There also is a #8 gauge bare copper wire that leaves the main box and exits through the exterior wall and follows down the side wall of the house, and enters the grade following the foundation cinder block. Is this adequate, or who would have this info available before the elect. inspector pays his inspection visit, and informs me that it may not be. I've read of grounding RODS, and I am unsure if the #8(I believe) would be considered as the rod.
Please critique freely any, and all points of this plan, for I wish to do this informed/educated/,and alive, so I may meet the heir inspector general.
The tub is a four wire set up(hot/hot/neutral/ground)
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Old 09-30-01, 02:24 AM
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You seemed to have a lot of these correct, but just to clarify...

A receptacle is required no closer than 10 feet and no farther than 20 feet from the inside wall of the hot tub. This is beyond any required outlets for hot tub operation. This outlet, and every outlet within 20 feet of the tub, needs to be GFCI protected (it's outdoors, so all outlets should be GFCI protected anyway).

No new lighting fixtures shall be installed within 5 feet horizontally of the inside wall of the pool, unless all portions of the fixture are at least 12 feet above the maximum water level.

Existing fixtures within the 5 foot horizontal area shall be at least 5 feet above the max water level, rigidly attached to the structure, and protected by a GFCI.

Switches shall be located at least 5 feet horizontally from the inside wall of the pool, unless separated by a permanent barrier such as a wall.

The disconnecting means shall be at least 5 feet from the inside walls, and within sight of the hot tub.

GFCI protection is required for the equipment (hot tub).

All fixed metal parts within 5 feet horizontally of the inside wall of the tub, and within 12 vertically of the maximum water height shall be bonded together with a #8 solid copper bond. This bond shall be installed to the disconnecting means enclosure which will serve as the common bonding grid.

A solid copper conductor, not smaller than #8 shall be run from the disconnecting means to the hot tub for bonding purposes. This conductor can also be used for equipment grounding.

Schedule 40 PVC is for underground installations, and schedule 80 PVC is for above ground installations.

#6 copper is a good size for your 50 amp circuit, #4 aluminum would also work (There are three assumptions on my part to reduce the size of these wires: 1-no romex or ser cable is used in the circuit 2-all terminations are rated for 75C in temperature, including the breaker, disconnect, and hot tub 3-you are not concerned about voltage drop). If my assumptions are correct, then you could run #8 cu or #6 al.

You should run PVC conduit through the bottoms of your cabinets through the garage, don't leave NM or SER cable exposed in the bottom of the cabinet! If you intend to run it through the dead space beneath the cabinet, your AHJ (inspector) may approve that, but I doubt it.

Enjoy your day, wiring a hot tub is one of the most challenging things you can do in a home.
Old 09-30-01, 05:40 AM
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You do not need the jumper to your metal siding of your home between the disconnect and the metal siding.

Check your hot tub to ensure that you don't have a GFCI breaker installed by the Manufacturer under the hot tub. If you have a GFCI breaker installed by the manufacturer under the hot tub then the disconnect is site can be served by this manufacturer's breaker without installation of a remote disconnect. Also if the GFCI breaker installed under the hot tub by the manufacturer then a second GFCI would not be required either in an unneeded disconnect in sight or in the main panel. All you would have to do is install a 50 amp breaker in the main panel and run your conductors direct connect to the hot tub manufacture installed GFCI and you are done with no other equipment required except the 8 awg bonding grid wire explained later.

If you do not have a disconnect form under you hot tub which I suspect you will find that you do. You can follow the next set of instructions pertaining to disconnects etc.

You can save some money if you install the GFCI breaker in the main panel and just use a non fused w/p disconnect outside within sight not closer than 5'.

Your required general use receptacle seems to be fine as long as it lands beyond 10' and within 20' of the hot tub.

Now I interpret different from S1nuber on his following statements;

This bond shall be installed to the disconnecting means enclosure which will serve as the common bonding grid.

A solid copper conductor, not smaller than #8 shall be run from the disconnecting means to the hot tub for bonding purposes. This conductor can also be used for equipment grounding.

The 8 awg bonding grid wire is not supposed to be connected to the disconnecting means enclosure. Number one it is beyond the 5' area and a bonding grid is not designed to be connected to the electrical system as its source. The bonding grid is designed to be a grid only with its source being all non current carrying metals within 5' of the hot tub and larger than 4" square or larger. The intent is to make all noncurrent carrying parts as one entity by connecting all of these non current carrying parts together only making all as one entity. No other connections including the electrical equipment grounding system shall be used in that bonding grid design. There are incidental connections between the two but only by coincedent. There is to be no specific connection of the bonding grid to any electrical grounding system at all other than by coincedent.

I do agree with S1nuber that you may run 6 awg but disagree that you may run 8 awg and protect it with a 60 amp breaker.

I also agree with S1nuber that you may install NM cable [Romex] from the inside panel through the inside of your dwelling to a J-box or non fused disconnect on the outside of the dwelling then switching to conduit with an insulated grounding conductor, and protecting the NM cable while inside the cabinits is also a good idea.

Remember that the equipment grounding conductor in that feeder is allowed to be protected by the sheath of the cable while inside the dwelling but must be insulated not just covered and must be in conduit while outside the dwelling structure. You are allowed to install conduit the entire run from the house panel to the hot tub but conduit is not required while inside the dwelling. The conduit and the insulated equipment grounding conductor protected by a conduit is required whild outside the dwelling structure only.

The bonding grid requires an 8 awg solid copper conductor to be connected to the lug on the metal case of the motors, the metal plumbing and any other non current carrying metal associated within 5' of that hot tub making all as one entity. No intentional connections are to be made with that 8 awg solid bonding grid wire to any electrical system or to any grounding electrodes such as ground rods.

Hope this helps


Old 10-01-01, 02:40 PM
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I thought that you might have a different view WG, it is good to see how others INTERPRET the code. I still don't like to use the word interpret, as it makes people think that we are working some sort of voodoo magic. I think that the code is very straightforward (with a few exceptions).

My first post states nowhere that you can put 8awg wire under a 60 amp breaker. 8awg is typically rated for 40 amps, but some cases can be made for 50 amps (not even including special items such as motors). This varies depending on the type of wire, and the connections the wire is made with. These items were covered under my assumptions, but I would run 6awg copper for voltage drop alone, if nothing else.

WG makes a great point about the bonding grid. In fact, he makes it twice for fun, I guess. IF you bond your siding (I don't think you need to either, but better safe than sorry), then installing the 8 from the tub to the disconnect, and from the siding to the disconnect would be easier than running everything to the tub. I was not very clear on that point, so follow WG on that one.

His explanation of the bonding vs. grounding needs of the grid are right on as well. Again, I was trying to reduce the effort and kill two birds with one stone while exceeding the code at the same time. If you don't bond the siding, you won't have to worry about my bonding scenario, so just follow WG. In fact, your tub probably will come with the 8 bond already installed in the tub to everything that needs to be bonded. If you just keep all metal 5 feet away from the tub, you won't have any concerns. This is much easier and cheaper.

Enjoy your day!
Old 10-01-01, 04:20 PM
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I love it when two knowledgable people, like to fight over me(JUST KIDDING. But aside I do appreciate the different veiwpoints on this saftey issue. You are the salt N pepper, oil & "WATER" of electrical voo doo guys.
THANKS for the advice.

p.s. If any further ideas on this subject, feel free to throw them this one's way. I'll get judge Miles Davis to referee. THANKS AGAIN Dave K.
Old 10-02-01, 12:48 PM
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Wire nuts, I was pointing out the bonding grid heavy because a lot of people in the industry misunderstand the purpose of a bonding grid and confuse this bonding grid with equipment grounding system and grounding system methods. Check a copy of the following NEC section for confirmation. The actual intent of a bonding grid is to contain electrical gradients from the electrical system from causing a shock hazard in the pool area geographically. These stray voltages are also found in the equipment grounding system due to leakage of motors, etc. While there are coincidental connection between the bonding grid system and the equipment grounding system those are allowed as the lesser of the evils in mixing these two systems. To do without the equipment grounding conductor at the circulating motor for instance you would lose a strongly needed protection. Yet to connect that equipment grounding conductor inside the motor and then connect the bonding grid on the outside case of the motor does cause these two systems to make contact. It is commonly thought that to make this incidental contact is better than to not have the equipment grounding conductor connected to protect from dead shorts causing the breaker to kick due to interrupting rating of the breaker. Kind of like a lessor of two evils in the desire to separate these bonding grid systems and the equipment grounding system.

Check below wording that was added in the 99 NEC

680-22. Bonding
It shall not be the intent of this section to require that the No. 8 or larger solid copper bonding conductor be extended or attached to any remote panelboard, service equipment, or any electrode, but only that it shall be employed to eliminate voltage gradients in the pool area as prescribed.

Hope this helps

Old 10-02-01, 06:52 PM
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You light up my world with the multitude of info you PRESENT. almost crosses my own wires sort of speak.
It's all interesting to say the least.

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